A photovoltaic cell can include a semiconductor layer deposited on a substrate, such as glass. For example, a continuous process for deposition of semiconductor material as a layer on a glass sheet substrate can rely on source material troughs in which the semiconductor material is received, within a heated processing chamber. The source material can be sublimed from the troughs to deposit the semiconductor material on a surface of glass sheets conveyed below the troughs. This construction requires that the source material troughs be replenished periodically. Alternatively, the source material can be conveyed by a carrier gas to a distributor which deposits the semiconductor layer on the substrate.